Hardboard is a cheaper option than plywood where strength is not required. Hardboard is made from wood fiber is extracted from chips and pulped wood waste. In the production process the pulp is exploded under pressure. Heat and steam is applies to leave a fine, fluffy brown fibers. These fibers are transformed into mats, which are held together with lignum and other glues. The mats are than pressed between steam-heated metal plates to give grain-less sheets with one smooth, glossy surface and one textured surface. To prevent warping, moisture is added in a humidification chamber.